Reaction Kinetics of Cinnamaldehyde Hydrogenation over Pt/SiO2: Comparison between Bulk and Intraparticle Diffusion Models

Abstract

The liquid-phase hydrogenation of cinnamaldehyde over a Pt/SiO2 catalyst was investigated experimentally and theoretically. The experiments were conducted in a 300 cm3 stainless steel stirred batch reactor supplied with hydrogen gas and ethanol as a solvent. Five Langmuir–Hinshelwood kinetic models were investigated to fit the experimental data. The predictions from the bulk model were compared with predictions from the intraparticle diffusion model. Competitive and non-competitive mechanisms were applied to produce the main intermediate compound, cinnamyl alcohol. Reaction rate parameters for the different reaction steps were calculated by comparing between the experimental and mathematical models. All rate data utilized in the present study were obtained in the kinetic regime. The kinetic parameters were obtained by applying a nonlinear dynamic optimization algorithm. Nevertheless, the comparison between the methodology of the present model and these five models indicated that the non-competitive mechanism is more acceptable and identical with the single-site Langmuir–Hinshelwood kinetic model including mass transfer effects and it mimicked the reactant behavior better than the other models. In addition, the observed mean absolute error (MAE) for the non-competitive mechanism of the present model was 2.3022 mol/m3; however, the MAE for the competitive mechanism was 2.8233 mol/m3, which is an increase of approximately 18%. The prediction of the intraparticle diffusion model was found to be very close to that of the bulk model owing to the use of a catalyst with a very small particle size (<40 microns). Employing a commercial 5% Pt/SiO2 catalyst showed a result consistent with previous research using different catalysts, with an activation energy of ≈24 kJ/mol.

Utilization of Loaded Cobalt onto MCM-48 Mesoporous Catalyst as a Heterogeneous Reaction in a Fixed Bed Membrane Reactor to Produce Isomerization Product from n-Heptane

“…As a result, the molecules of the reactant react and leave the pores of the catalyst prior to the development of any selectivity [50]. Chica and Corma (1999) investigated production of gasoline with high octane number through hydroisomerization of n-heptane to dibranched and tribranched components where different zeolites such as unidirectional 12 Membered Ring (MR) zeolites having various pore sizes were employed [51].…”

The mathematical catalyst deactivation models: a mini review

“…Accordingly, the non-linear interference is bound by the catalyst activity, operating conditions and composition of the reaction mixture. 20,123 These differential equations usually describe the fourthorder Runge-Kutta integration method. The kinetic and deactivation parameters were obtained by benchmarking the experimental and predicted results using a stochastic optimization method.…”

“…Accordingly, the non-linear interference is bound by the catalyst activity, operating conditions and composition of the reaction mixture. 20,123…”

Preparation and Characterization of Mercapto-Functionalized Calcined Attapulgite and Its Removal of Pb (II) and Cd (II) Solution

“…An investigation of adsorption kinetics can provide valuable information about the mechanism of adsorption. The experimental data can be analyzed using various models, including the Pseudo-first-order model [26], Pseudo-second-order [27], Elovich [28], Intraparticle diffusion [29] models and Double constant equation [30] to determine important parameters related to the adsorption process.…”